With the sudden popularity of the Internet, many important tasks involving financial transactions, information exchange, etc, are performed in a computer network. Security when communicating in computer networks is a major concern that has to be attended to.
As such, cryptography allows only a specific group to share information and prohibits other parties other than the specific group communicating to access the contents of the information so as to secure communication. To achieve such an objective, cryptography must be accurately deciphered by the group using cryptography as a security measure while not allowing the information to be deciphered by a third party.
Presently, public key cryptographic technology such as Rivest, Shamir, Adleman (RSA) technology is mainly being used. However, most currently used cryptography methods, such as RSA technology, do not strictly provide security since such technologies are based on conditional security that is substantially difficult to be solved. As computer technology, quantum computers, and a new and effective algorithm are developing, cryptography is solved.
A quantum cryptography method of ensuring security using a quantum-mechanical characteristic of light has been recently developed as a method of solving this problem.
A quantum cryptography is a cryptographic system that fundamentally prevents wiretapping from occurring during an exchange of cryptography keys since quantum cryptography is based on quantum physics.
Since a person communicating can use quantum cryptography to tell if the line is being tapped, quantum cryptography can be utilized to ensure a secure communication
A physical natural phenomenon, but not a mathematical technique, is used as a system to prevent tapping since converting a signal during a communication session is useless. Thus, a method of tapping quantum cryptography does not originally exist.
A basic system for realizing quantum cryptography uses a linear polarization photon as a principle.
An optical fiber-based quantum cryptography system has been developed in technology for actively compensating polarization and phase (or path) fluctuation of an optical signal occurring during a transmission of an optical signal through a transmission optical fiber. Thus, auto-compensating quantum cryptography technology for passively compensating polarization and path fluctuation using a Faraday mirror has been invented by the Gisin faculty et al. in the Swiss Geneva University.
In an auto-compensating quantum cryptography system, an optical pulse signal having a strong intensity transmitted from a quantum cryptography receiver Bob to a quantum cryptography transmitter Alice meets a pulse with an intensity of a single photon being fed back from the quantum cryptography transmitter to the quantum cryptography receiver in a transmission optical fiber.